The main direction of the project is immunological involving complement interactions with immune systems as part of a continuing interest in the autoimmune diseases and the role serum complement. The ultrastructural applications include: (1) electron microscope studies of human complement components and their molecular interaction with each other and immunoglobulins; (2) and ultrastructural studies to determine the spatial relationship of complement components to complement induced "holes". The first project concentrates on the ultrastructure of Clq and its interaction with immunoglobulins. In the second Clq and C4 have been shown to have no spatial relationship to the "holes" but the later acting components have not been examined. Project (3) involves a morphological study of Bordetella pertussis including localization of biologic activities (especially lymphocyte and histamine sensitizing activities) to one of two structural entities present in the bacterial cell wall and liquid culture (supernatants). This collaborative study with Dr. S.I. Morse (Downstate Medical Center) has already achieved separation of these two ultrastructural particles by cesium chloride centrifugation. Immunochemical and further biological correlations are planned with each of the isolated particles and specific antisera prepared against them. The (4) project is concerned with a search for viral particles in immune precipitates formed from blood and synovial fluids of patients with autoimmune diseases. A new study includes the purification and characterization of an immunosuppressive peptide from plasma.